Various conventional methods for producing an iodine compound have been known. Examples of the conventional methods for producing an iodine compound are disclosed in Patent Literatures 1-7 and Non-Patent Literatures 1-3 below.
Patent Literature 1 discloses a method for adding iodine to an alkaline solution and reacting the iodine with the alkaline solution to produce iodate, and thereafter reducing the produced iodate with aluminum or zinc. Patent Literature 2 discloses a method for adding iodine to an alkaline solution and thereafter reducing the iodine with hydrogen sulfide. Patent Literature 3 discloses a method for reducing iodine or iodate with alkaline metal amalgam in an alkaline circumstance or a neutral circumstance. Patent Literature 4 discloses a method for adding an organic reductant such as formic acid, oxalic acid, and malonic acid to an alkali hydroxide solution of iodine and reacting the alkali hydroxide solution of iodine. Patent Literature 5 discloses a method for adding iodine to a potassium hydroxide solution and thereafter adding formic acid as a reductant to the solution. Patent Literature 6 discloses a method for causing iodine to react with potassium hydroxide or alkali carbonate using hydrazine as a reducer. Patent Literature 7 discloses a method for adding formic acid to a potassium hydroxide solution and neutralizing the solution and thereafter adding iodine with an amount larger than stoichiometric quantity to the solution so as to make the iodine react, and processing isolated iodine in the resulting with potassium sulfide. Patent Literature 8 discloses a method for producing hydrogen iodide by catalytic reduction of hydrogen-containing gas and gaseous iodine using platinum catalyst highly dispersed in oxide or activated carbon, and a method for collecting generated hydrogen iodide gas using water or an alkali aqueous solution.
Further, Non-Patent Literature 1 describes a method for flowing, over 100° C.-heated platinum, hydrogen current in which iodine is saturated. Non-Patent Literature 2 discloses a method for producing potassium iodide by mixing and neutralizing hydriodic acid with potassium hydrogen carbonate and processing unreacted iodine with hydrogen sulfide in a weak alkaline circumstance. Non-Patent Literature 3 discloses a method for crystallizing potassium iodate which is by-produced when synthesizing potassium iodide from iodine and potassium hydroxide, and heating potassium iodate at 600° C. to decompose and remove potassium iodate.
Conventionally, a general method of producing hydrogen iodide used as a raw material of an iodine compound is to obtain hydrogen iodide by chemically reacting red phosphorus, water, and iodine. Further, another methods for producing hydrogen iodide (or hydriodic acid) include techniques disclosed in Patent Literatures 9-16.
The following specifically explains the techniques disclosed in Patent Literatures 9-16. Patent Literature 9 discloses a method for producing hydriodic acid from iodine with use of a phosphorous acid aqueous solution, a pyrophosphoric acid aqueous solution or the like as a reducer. Patent Literature 10 discloses a method for producing hydriodic acid from water, sulfur dioxide, and iodine. Patent Literature 11 discloses a method for hydrogen iodide from ammonium and iodine in the presence of an iron catalyst. Patent Literature 12 discloses a method for producing anhydrous hydrogen iodide by reaction among a phosphorus acid aqueous solution, diphosphorus pentoxide, and metal iodide. Patent Literature 13 discloses a method for producing hydrogen iodide from iodine and tetrahydronaphthalene. Patent Literature 8 discloses a method for producing hydrogen iodide by catalytically reducing hydrogen-containing gas and gaseous iodine in the presence of a catalyst. Further, Patent Literatures 14-16 disclose a method for producing hydrogen iodide with high purity by an electrochemical method.
[Patent Literature 1] U.S. Pat. No. 2,828,184, specification
[Patent Literature 2] U.S. Pat. No. 3,402,995, specification
Patent Literature 3
Japanese Examined Patent Application Publication, Tokukousho, No. 31-8013
[Patent Literature 4] Japanese Patent Application Publication, Tokukaihei No. 1-261224
[Patent Literature 5] Russian Patent No. 560826, specification
[Patent Literature 6] Japanese Patent Application Publication, Tokukaisho No. 61-48403
[Patent Literature 7] Russian patent No. 497233, specification
[Patent Literature 8] Japanese Patent Application Publication, Tokukai No. 2005-255514
[Patent Literature 9] Japanese Patent Application Publication, Tokukaihei No. 8-59205 (published on Mar. 5, 1996)
[Patent Literature 10] U.S. Pat. No. 4,150,094, specification (published on Apr. 17, 1979)
[Patent Literature 11] U.S. Pat. No. 3,278,264, specification (published on Oct. 11, 1966)
[Patent Literature 12] Japanese Patent Application Publication, Tokukaihei No. 9-86902 (published on Mar. 31, 1997)
[Patent Literature 13] U.S. Pat. No. 4,357,309, specification (published on Nov. 2, 1982)
[Patent Literature 14] Japanese Translation of PCT International Application, Tokuhyohei No. 11-503203 (published on Mar. 23, 1999)
[Patent Literature 15] U.S. Pat. No. 4,053,376, specification (published on Oct. 11, 1977)
[Patent Literature 16] Japanese Patent Application Publication, Tokukaihei No. 9-54197 (published on Feb. 25, 1997)
[Patent Literature 17] European Patent No. 0714849, specification (published on Jun. 5, 1996)
[Patent Literature 18] Japanese Patent Application Publication, Tokukai No. 2005-289936 (published on Oct. 20, 2005)
[Non-Patent Literature 1]
Kagakudaijiten hensyuiinkai (ed.), “Kagakudaijiten”, reduced-size 28th edition, Kyoritsu Shuppan Co., Ltd., Mar. 15, 1984, Vol. 9, p 410
[Non-Patent Literature 2]
The Chemical Society of Japan (ed.), “Shinjikkenkagakukouza”, MARUZEN Co., Ltd., Mar. 20, 1977, Vol. 8, p 522
[Non-Patent Literature 3]
Jacqueline I. Kroschwitz, “Encyclopedia of Chemical Technology”, Forth edition, JOHN WILEY ft SONS, 1996, Vol. 19, p 1084